The present invention is generally directed to providing reliable cooling systems for mainframe computer systems or for any electronics system requiring cooling. More particularly, the present invention is directed to an auxiliary thermal buffer unit employed with a primary cooling system or with redundant cooling systems to cool an electronics device such as an electronics module.
In recent years, the semiconductor industry has taken advantage of the fact that CMOS circuits dissipate less power than bipolar circuits. This has permitted more dense packaging and correspondingly faster CMOS circuits. However, almost no matter how fast one wishes to run a given electronics circuit chip, there is always the possibility of running it faster if the chip is cooled and thermal energy is removed from it during its operation. This is particularly true of computer processor circuit chips and even more true of these chips when they are disposed within multichip modules (MCMs), which generate significant amounts of heat. Because there is a great demand to run these processor modules at higher speeds, the corresponding clock frequencies at which these devices must operate become higher. In this regard, it should be noted that it is known that power generation rises as a function of the square of the clock frequency. Accordingly, it is seen that the desire for faster computers generates not only demand for computer systems but also generates thermal demands in terms of energy which must be removed for faster, safer and more reliable circuit operation. In this regard, it is to be particularly noted that, in the long run, thermal energy is the single biggest impediment to semiconductor operation integrity.
In addition to the demand for higher and higher processor speeds, there is also a concomitant demand for reliable computer systems. This means that users are increasingly unwilling to accept down time as a fact of life. This is particularly true in the mainframe and server realms when zero down time and minimum maintenance requirements are typical goals. There are yet other requirements that must be met when designing cooling units for computer systems, especially those which operate continuously and which may in fact be present in a variety of different thermal environments. For example, the cooling system should be designed, controlled and set up so that various failure modalities do not bring the entire computer system down nor risk damage to the components within the system. All of these requirements must be considered in providing a cooling system for a computer system, particularly for a mainframe and/or server system.
To briefly summarize, the present invention comprises in one aspect a cooling system, e.g., for an electronics module. The cooling system includes a cooling unit, and an evaporator plate having at least one isolated refrigerant loop therein for receiving coolant from the cooling unit. The system further includes a thermal buffer, which is thermally coupled to the evaporator plate and which maintains temperature of the evaporator plate within a predefined range for a period of time upon shut down or failure of the cooling unit.
In another aspect, the invention comprises a cooled processing stack. The cooled processing stack includes an electronics module having a main surface to which a cooling system is thermally coupled. The cooling system includes a cooling unit and an evaporator plate having at least one isolated refrigerant loop therein for receiving coolant from the cooling unit. In addition, the cooling system includes a thermal buffer which is thermally coupled to the evaporator plate to maintain temperature of the evaporator plate within a predefined range for a period of time upon shut down or failure of the cooling unit.
In a further aspect, the invention comprises a method of fabricating a cooling system for an electronics module. The method includes providing a refrigeration cooled cold plate, and thermally coupling the thermal buffer unit to the cold plate. The refrigeration cooled cold plate is thermally coupled to the electronics module for removing heat generated by the module. When in operation, the thermal buffer unit is thermally coupled to the electronics module across the refrigeration cooled cold plate for auxiliary cooling of the module upon shut down or failure of the refrigeration cooled cold plate.
Accordingly, it is an object of the present invention to provide a system and method for cooling computer and other electronics systems.
It is another object of the present invention to provide a cooling system which possesses redundancy for the purpose of providing uninterrupted use of electronics equipment.
It is a still further object of the present invention to provide a cooling system for electronics assemblies, modules and cards.
It is also an object of the present invention to provide a cooling system for electronics components which include fail-safe means for operation in the event of a number of different failure modalities, including refrigerant leakage.
It is also an object of the present invention to provide a system and method for continued computer usage in the event of cooling system problems.
It is a still further object of the present invention to provide a cold plate for electronics component cooling which preserves refrigerant flow isolation while at the same time maintaining good thermal connectivity to a module to be cooled and also provides good thermal conduction and flow-wise isolation between dual refrigerant loops.
It is a still further object of the present invention to provide an electronics component cooling system which is self-contained.
It is also an object of the present invention to provide a computer or electronics system in which the refrigerant cooling system is a rack-mountable, field-replaceable unit.
It is also an object of the present invention to provide a cooling system for an electronics module which can be attached to a refrigeration system by means of flexible and detachable refrigerant supply lines.
It is yet another object of the present invention to provide a refrigeration unit which is capable of operating continuously.
It is still another object of the present invention to provide a refrigeration unit which is capable of variable heat removal capacity, particularly in response to varying thermal demands.
It is a still further object of the present invention to provide a refrigeration unit which is easily startable, easily shut down and is capable of running under low thermal load situations.
It is also an object of the present invention to provide a refrigeration system which is capable of operating in a wide range of ambient and thermal load conditions.
It is still another object of the present invention to provide a hybrid auxiliary cooling system for an electronics module which combines a refrigeration cooled cold plate and an auxiliary thermal buffer unit.
It is a still further object of the present invention to provide a hybrid auxiliary cooling system which provides for continued cooling of an electronics component for a period of time notwithstanding inoperability of a refrigeration cooled cold plate coupled to the electronics module.
It is also an object of the present invention to provide for enhanced ambient cooling of a computer system commensurate with cooling of an electronics module of the computer system.
It is yet another object of the present invention to provide a hybrid auxiliary cooling system having a refrigerant cooled cold plate coupled to either a standard chiller unit supplying chilled water to the cold plate or an evaporation refrigerator supplying a refrigerant to the cold plate.
Lastly, but not limited hereto, it is an object of the present invention to provide a system and method for facilitating the operation of computer systems at higher speeds and, in particularly, for doing so in a reliable manner so as to be able to maintain such systems in continuous operation for as long a time as is reasonably possible.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention.